The production of ultra-high molecular weight, high density polyethylene with single site catalysts has been accomplished. For instance, U.S. Pat. No. 6,265,504 discloses a process for preparing an ultra-high molecular weight, high density polyethylene with a heteroatomic ligand-containing single site catalyst and a non-alumoxane activator. Similarly, U.S. Pat. Nos. 6,767,975 and 7,091,272 disclose the preparation of ultra-high molecular weight polyethylene using a combination of a pyridine moiety-containing single site catalysts and clay. The polymerization is performed in the absence of α-olefins and the resulting ultra-high molecular weight polyethylene also has high density.
Although ultra-high molecular weight, high density polyethylene exhibits remarkable toughness and durability, it can suffer from low impact and tear strengths. Linear low-density polyethylene exhibits higher impact and tear strengths. A polyethylene that combines the advantages of ultra-high molecular weight polyethylene with the advantages of linear low density polyethylene would be useful.